Study the pedigree chart of a family showing the inheritance of myotonic dystrophy.

 

The trait under study is 

1. dominant X-linked

2. recessive X-linked

3. autosomal dominant

4. recessive Y-linked.

If a homozygous red flowered plant is crossed with a homozygous white flowered plant and red colour allele  is completely dominat over white colour allele, the offspring would be 

(1) half red-flowered

(2) all red-flowred

(3) half white-flowered

(4) half pink- flowered.

One of the genes present exclusively on the X-chromosome in humans is concerned with

1. baldness

2. red-green colour blindness

3. facial hair/moustaches in males

4. night blindness

Which one of the following pairs of features is a good example of polygenic inheritance?

(1) Human height and skin colour

(2) ABO blood group in humans and flower colour of Mirabilis jalapa

(3) Hair pigment of mouse and tongue rolling in humans

(4) Human eye colour and sickle cell anaemia

Mating of an organism to a double recessive in order to determine whether it is homozygous or heterozygous for a character under consideration is called

(1) reciprocal cross

(2) test cross

(3) dihybrid cross

(4) back cross

Which of the following is correct ?

(1) Henking discovered the small Y-chromosome.

(2) Drosophila also shows XX-XY sex determination like human.

(3) Birds have ZZ-ZW sex determination, where females are ZZ and males are ZW.

(4) Grasshoppers show XX-XY sex determination. 

Which of the following occurs due to monosomy of sex chromosome?

1. Down's syndrome

2. Turner's syndrome

3. Haemophilia

4. Sickle cell anaemia

If 'A' represents the dominant gene and 'a' represents its recessive allele, which of the following would be the most likely result in the first generation offspring when Aa is crossed with aa ?

1. All will exhibit dominant phenotype.

2. All will exhibit recessive phenotype. 

3. Dominant and recessive phenotypes will be 50% each.

4. Dominant phenotype will be 75%.

In a plant, red fruit (R) dominant over yellow fruit (r) and tallness (T) is dominant over shortness (t). If a plant with RRTT genotype is crossed with a plant that is rrtt. Then

(1) 25% will be tall with red fruit

(2) 50% will be tall with red fruit

(3) 75% will be tall with red fruit

(4) All of the offspring will be tall with red fruits 

A pea plant parent having violet-coloured flowers with unknown genotype was crossed with a plant having white-coloured flowers. In the progeny, 50% were white. The genotypic constitution of the parent having violet-coloured flowers was

1. homozygous

2. merozygous

3. heterozygous

4. hemizygous